Ultra-Processed Foods: An Introduction

Ultra-Processed Foods: An Introduction

This article is from the Nutrition section of our Library.

About This Series

This is Article 1 of a 4-part series exploring ultra-processed foods: what they are, how they came into existence, how they affect your health, and how to stop eating them.

  • Article 1: What Are Ultra-Processed Foods? (you are here)

  • Article 2: Why Ultra-Processed Foods Are So Popular (next week)

  • Article 3: Health Effects of Ultra-Processed Foods (in 2 weeks)

  • Article 4: Reducing your intake of Ultra-Processed Foods (in 3 weeks)

Introduction

Supermarkets are filled with foods ranging from minimally changed to barely recognisable food by industrial processes. 

These differences matter because emerging research suggests that how food is processed may affect your health, over and above the nutritional content of the food alone.

Ultra-processed food (UPFs) have become a focus of health and nutrition science over the past decade. But before we look further into UPFs, it is useful to define what a UPF is and how they can be identified.

    NOVA Classification

    In 2009, researchers at the University of São Paulo introduced a “framework” categorising foods based on the processing they’ve been through and what they’re used for. This system divides foods into four groups.

    Group 1: Unprocessed and Minimally Processed Foods

    These are foods in their natural state or altered only slightly. Examples include fresh vegetables, fruits, eggs, milk, plain yoghurt, dried beans, and frozen vegetables. Processing here is minimal: washing, removing inedible parts, drying, freezing, or pasteurising for safety are fine.

    Group 2: Processed Culinary Ingredients

    This group includes extracts from Group 1 foods that are used in cooking. Think olive oil, butter, sugar, salt, and honey. You wouldn't (or shouldn’t) eat these alone as meals, but they help prepare other foods.

    Group 3: Processed Foods

    These foods result from adding Group 2 ingredients to Group 1 foods. The goal is to preserve or improve flavour. 

    Canned vegetables with salt, tinned fish in oil or brine, freshly made bread with just flour, water, yeast, and salt, and simple cheeses fall into this category. These foods aren’t inherently bad (in limited amounts), as they still retain a lot of their original nutritional value.

    Group 4: Ultra-Processed Foods

    This category includes products that are made mostly or entirely from substances derived from food and additives. Little of the Group 1 food is intact. 

    To make these foods, they use industrial processes like hydrogenation, extrusion, moulding, and pre-processing for fractionation. The result is products designed for convenience, palatability, and shelf life — not nutrition (or health).

    What Makes a Food Ultra-Processed?

    There’s no single quick rule that you can define UPFs, but there are several things to look out for that they all have in common.

    1. Industrial Formulation: UPFs are typically created in factories rather than kitchens. They contain ingredients rarely used in home cooking: protein isolates, modified starches, hydrogenated oils, and artificial additives. They’re added for flavour, texture, or shelf-life, not for nutrition.


    2. Multiple Processing Steps: The creation of UPFs involves several industrial processing techniques. A single product might undergo extrusion, moulding, preprocessing, and hydrogenation. 

    Studies indicate these processes alter the food in ways that negatively affect digestion and metabolism for health.


    3. Ready to Consume: Most UPFs require little or no preparation. They're designed for immediate consumption or simple heating. This convenience means you're more likely to eat them, and more of them, more often.


    4. Palatability Engineering: Manufacturers formulate UPFs to maximise taste by combining fat, sugar, salt, and other flavourings. 

    While these ingredients aren’t inherently harmful, they tend to be overconsumed (compared to minimally processed alternatives), which negatively impacts health.


    5. Number of ingredients: While not a perfect rule, UPFs typically have long ingredient lists containing things you wouldn't find in a home kitchen. 

    Look for unfamiliar items like maltodextrin, modified corn starch, protein isolate, or various numbered additives. Having a long ingredient list doesn’t define a UPF by itself, as some wholesome foods have many ingredients.


    6. Packaging and Marketing: UPFs typically come in manufactured packaging with health claims and appealing graphics. They're typically colourful and positioned as convenient meal replacements or snacks. 

    The package might emphasise fortification with vitamins or minerals, attempting to convey nutritional value.


      Typical examples of UPFs include: soft drinks, packaged snacks, mass-produced bread, sugary breakfast cereals, instant noodles or rice snacks, energy bars, chicken nuggets, hot dogs, and shelf-stable meals. 

      Notably, price doesn't determine processing level; both budget and premium products can be ultra-processed.


      Diet Atlas Guide

      Grey Areas

      Not everything fits neatly into these four categories. Some products fall outside and occupy a middle ground. For example, plant milks, protein powders, protein bars, flavoured yoghurts, and “whole-grain” products. 

      Some of these products can be made with natural ingredients, sweeteners, and minimal processing (or even at home). 

      However, other products in the same category contain artificial additives, preservatives, flavourings and have been through multiple rounds of processing. Not all products are created equal.

      These grey areas highlight a limitation. So the classification system is a tool, not a rule. Don’t expect them to accurately capture and classify every product you buy at the supermarket. 

      Why do we need definitions anyway? 

      The short answer is the consumer probably doesn’t. No one is going to go around the supermarket with a 26-point checklist, checking to see which group every item on your list is before putting it into your basket. 

      However, researchers require strict definitions so they can analyse them. 

      How many UPFs do people eat? How many UPFs do different groups of people eat? How do they affect health? What type of UPFs do people eat? Why do people eat UPFs? What would happen if we taxed UPFs or limited their availability? How can consumers identify or be aware of UPFs? 

      All these questions require strict criteria to define them. But as individuals, most of us don’t have to worry about rigid rules and technical definitions. 

      Eating the occasional UPFs isn’t going to negatively affect your health by itself; problems arise when UPFs dominate your diet, eaten daily in place of healthy foods.

      Context matters. Someone with limited time, resources, or access to fresh food might rely more on UPF options. That's a practical reality, not a moral failing. The goal of the classification of UPFs at this stage isn't about judgment but understanding what they are.

      Looking Ahead

      UPFs are now embedded in many food systems around the world. Defining them is just the first step. How did these products become so widespread? What factors drove their expansion from niche convenience items to dietary staples?

      Next in this series: Why UPFs Became So Popular

      Disclaimer: No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.